About 2 percent of the revenue last year came from liver supplements, which surged 114 percent from 2015 to VND89 billion.

The company planned to more than double sales of liver supplement brand Naturenz to VND800 billion, accounting for 12 percent of total revenues in the next five years.

In pill form, liver supplements marketed for detoxication and supporting liver functions have become big business for local pharmaceutical companies, Rong Viet Securities said.

Some major pharmaceutical companies have gradually reduced their antibiotics business in favor of other medicines, including supplements, in hope for greater profits.

Hau Giang’s revenues from antibiotics fell to 40 percent of the firm's revenue last year, from 45 percent in 2008, based on financial reports. It has projected the antibiotics sales to fall further to 38.5 percent of revenue by 2020.

Traphaco, Vietnam's second-biggest listed pharmaceutical company, reported that sales of its liver detox brand Boganic had doubled within a five-year period to VND200 billion in 2015 and that the sale has been rising 16 percent annually in recent year.

Each Vietnamese person drank on average 42 liters, making the country Asia's third biggest beer consumer after Japan and China, and Vietnam ranks among the world’s top 25 heaviest beer drinkers. Demand for liver detox has been rising in line with higher consumption of alcoholic drinks.

Over the past five years, Vietnam has doubled its beer consumption to more than 3 billion liters per year. Last year it produced an estimated 3.8 billion liters of beer, up 18 percent from 2015, based on government data. Its well-known export brands include Bia Saigon and 333.

The country has projected beer production to rise to 4.1 billion liters in 2020, based on a Industry and Trade Ministry plan.